Molding compositions containing triketoimidazolidine precondensates, their use, and a process for preparing a triketoimidazolidine precondensate composite suitable for this purpose

ABSTRACT

Molding composition containing 
     (a) 2,4,5-triketoimidazolidine precondensates containing terminal oxamide ester, urethane and/or isocyanate groups and 
     (b) customary organic and/or inorganic fillers, which contains the triketo compound (a) in the form of an amorphous precondensate as a reactive filler and 
     (c) at least one further reactive component of a binder from the group consisting of phenolic resins, amine resins, epoxide resins, polyester resins, hydrocarbon resins containing functional groups and/or polymerization resins containing functional groups; their use for manufacturing radiation-, light- and/or heat-resistant and/or abrasion-resistant shaped articles.

It is known to prepare molding compositions containing inorganic and/ororganic fillers. Asbestos fibers have hitherto been extensively used forthis purpose, owing to their favorable physical properties, such asrefractoriness, high abrasion resistance and high hardness. For example,mixtures of this type exhibited high friction when used as brakelinings. As is known, asbestos is a crystalline natural product. Theprocessing of these crystals is associated with the serious disadvantagethat respiratory organs are considerably impaired, so that even lungcancer can arise. Demands have therefore been made for some time toreplace this fiber as far as possible.

It is also known to produce "aramide fibers" based on terephthalicchloride and p-phenylenediamine ("Research Disclosure", February 1980,pages 74/75) and to process these fibers in the form of a pulp of finefibers (fibrilated) of various lengths to give flat articles such aspaper, if appropriate combined with other fibers such as those based oncellulose, polyester, polyamide or asbestos.

Another publication ("Textile Institute and Ind.", February 1980)describes the use of aramide fibers as an inner textile lining forrubber articles, in particular for automotive tyres, as reinforcers forplastics and for various applications, not mentioned in particular, inthe automotive sector and in aeronautics and space travel. Thispublication also mentions the replacement of asbestos or glass fibers inclothing coated with aluminum. It is also known to use these fibers as areplacement for asbestos in clutches and brake linings("Plastverarbeiter", volume 31, 1980, pages 527 and 528).

However, these aramide fibers have the disadvantage that, like asbestos,they are crystalline, that the polycondensation is very involved andthat spinning takes place from concentrated sulfuric acid at an elevatedtemperature, for example 80° C. This presents considerable practicaldifficulties. The crystalline character of these fibers requires anadditional stretching and orienting process, so that the manufacturebecomes relatively complicated.

It has also already been proposed to use carbon fibers for clutches andbrake disks. However, under thermal stress and strain there is the riskof a structural change from the diamond lattice to the graphite latticewith the result that the strength and hardness are impaired andgraphite-like sliding properties are produced. It is also known thatunder certain conditions carbon is absorbed from such fibers by metals(for example steel) and leads to an impairment of the properties, forexample through metal carbide formation.

The preparation of triketoimidazolidine rings from oxamates andisocyanates and, if appropriate, polycarboxylic acids while formingcondensation products containing amide and/or imide groups is alsoknown. It has also already been proposed to use these condensationproducts containing amide and/or imide groups for producing fibers,shaped articles and surface coatings containing mineral fillers,preferably glass fibers or graphite.

To avoid the abovementioned problems the object of the present inventionis to replace asbestos fibers in molding compositions as far as possibleby another filler which does not require as complicated a method ofproduction as the known aramide fibers and which, in addition, is lesscrystalline, i.e. to the extent even of having an amorphous structurewith the associated benefits.

The invention relates to a molding composition containing (a)2,4,5-triketoimidazolidines containing terminal oxamide ester, urethaneand/or isocyanate groups and (b) customary organic and/or inorganicfillers, and which contains the triketo compound (a) in the form of anamorphous precondensate as a reactive filler and (c) at least onefurther reactive component of a binder from the group consisting ofphenolic resins, amine resins, epoxide resins, polyester resins,hydrocarbon resins having functional groups and/or polymerization resinshaving functional groups.

The invention also relates to the use of such molding compositions forpreparing radiation-, light- and/or heat-resistant and/orabrasion-resistant shaped articles, for example in the form ofabrasion-resistant structural members, and, in particular, for preparingbrake linings, clutch disks or cylinder head seals.

Unlike the known aramide fibers, the triketoimidazolidine fillers usedaccording to the invention can be prepared in the form of a pulp byspraying, namely directly by extruding a solution in organic solventsthrough suitable nozzles into a coagulation medium, for example water.Working with concentrated sulfuric acid at an elevated temperature isthus avoided. Safety at work is increased thereby. These small particlesare obtained in amorphous form, that is in the form of small, irregularparticles, which implies a large specific surface area. This factlikewise ensures a high capacity for binding the reactive componentssimultaneously present in the mixture according to the invention, thefillers and, if present, other reinforcing materials. However, thesetriketo compounds can also be processed by simply spinning them, notonly by the wet method but also by the dry method, into filaments of anytiter. A particular advantage of the triketo compounds is that it isalso possible to produce fibers in a dry-spinning process, without theuse of added solvents not already present, and of water, for example inthe stretching stage or for washing, i.e. that it is possible to obtaina solvent-free, stretched yarn by using a dry-spinning process alone ortogether with a heat treatment. All these filaments can be processedwithout problems even into fibers cut to a very short length, forexample to about 2.6 mm.

The triketo compounds used according to the invention also permit theproduction of pulverulent or pulpy products by spray-drying.

If such molding compositions contain the triketoimidazolidineprecondensates in the form of fiber or pulp material, asbestos fiberscan be replaced in the manufacture of brake linings and of other shapedarticles, for example frictional linings, seals structural members. Theuse of pulp of such precondensates does not cause any problems in thepreparation and processing of the mixtures, and the heat resistance andthe adhesive and binding capacity of the pulp in the moldingcompositions are excellent. Furthermore, the frictional liningsmaufactured therewith are distinguished by good wear properties.

However, it has also been found that the properties of the moldingcompositions, and of the shaped articles produced therefrom, can beimproved still further when the 2,4,5-triketoimidazolidine compound (a)used is an amorphous precondensate containing terminal oxamide ester,urethane and/or isocyanate groups in the form of a composite of (a₁) a2,4,5-triketoimidazolidine precondensate pulp and (a₂) a pulp of otherfiber-forming polymers or, instead of this pulp (a₂), fibers made of2,4,5-triketomidiazolidines and/or other materials. The composite ispreferably prepared by injecting the solution of a2,4,5-triketomimdazolidine precondensate into a suspension of fibers.

Molding compositions obtained in this improved embodiment aredistinguished by the fact that composites made of triketoimidazolidineprecondensate pulp (shortened to "pulp" below) effect not only excellentfrictional, sealing and solidification properties but also an increasein the thermal stability under load in seals. The composites usedaccording to the invention can easily and homogeneously be incorporatedin the molding compositions, and do not cause any lumps even in the caseof very fine fibers of less than 3 dtex and short lengths of less than10 mm. Phenomena of the type occasionally encountered in the case ofmolding compositions which contain suspended fibers which, for examplein a calendering system to give stuctural members and seals, areoriented in such a way that they are incorporated in the moldingcompositions in a parallel arrangement and then exert the reinforcingand solidification properties desired only in this one direction, namelyparallel to the fiber axis, do not arise when using composites proposedaccording to the invention. In addition, the tensile strength and theinitial modulus are further increased, a fact which has a beneficialeffect in some areas of application, such as clutch linings.

Those composites are particularly preferably used in which the fibersused are firmly bonded in tangled position to the pulp and are verylargely present in tangled position even after the processing intoshaped articles. In particular those composites of pulp and fibers wherethe fibers are bound in complete tangled position can exert theirreinforcing capacity in the molding compositions isotropically in alldirections, a feature known hitherto only from asbestos, and can behomogeneously distributed and readily incorporated without difficulty inthe molding compositions, where not only the favorable properties of thepulp, for example adhesion promotion, heat resistance and abrasionresistance, but also those of the fibers used, for example high tensilestrength and high initial modulus, complement or add to, one another inan optimal manner.

Composites of this type can advantageously be prepared by spraying, inparticular by extruding, a precondensate solution in organic solvents,preferably aprotic ones miscible with water, through suitable nozzlesinto a suspension, for example a slurry, of the reinforcing fibers in acoagulation bath in which the precondensate and the fiber are notsoluble, for example into water. The coagulation medium used can,however, also be solvents which are not miscible with water and whichcan be easily separated, for example by distillation, from the aproticsolvent, such as toluene, xylene and higher alcohols, whereby therecovery of the aprotic solvents can in many cases be facilitated.Possible solvents are aprotic solvents, in particularN-methylpyrrolidone or even dimethylformamide, dimethylacetamide,dimethyl sulfoxide or cyclohexanone.

In another method for preparing the composites, precondensate and fibersof suitable length, for example of the length indicated below, aresimultaneously sprayed through a multimaterial nozzle in a sprayingtower or on other suitable units.

Suitable fibers are the known commercially available products, forexample those having a relatively high initial modulus and good heatresistance, such as polyaramides, for example the polyamides ofisophthalic or terephthalic acid with m- or p-phenylenediamine,polyacrylonitriles, namely homopolymers and copolymers with, forexample, acrylates such as those of methanol and ethanol,polyoxadiazoles, polybenzimidazoles, fibers based on phenolic resins orcellulose, such as rayon and cellulose acetates, carbon fibers and ofcourse also fibers made of polytriketoimidazolidines. The length andthickness of the fiber can be varied within wide limits according to theintended use. The fiber thickness is general between 0.2 and 12,preferably between 0.4 and 6 dtex. The length is in general from 1 to100 and preferably from 3 to 10 mm. The use of mixtures of various fibertypes is also possible and can be advantageous for certain purposes.

The ratio of pulp to fiber in the composite can also be varied withinwide limits, which are affected also by the length and thickness of thefiber. The ratio of pulp to fiber is in general 5:1 to 1:5, preferably3:1 to 1:3.

If the composite is prepared by the coagulation method, theconcentration of fiber in the coagulation bath is generally 1-20 g/l. Inthe case of spraying in the spray tower, amount and temperature of thespraying air and of the type of spraying nozzle used must be adapted tothe chemical nature of the fiber and especially to its length andthickness.

The choice of fiber component i.e. its chemical composition, has ofcourse an effect on the application areas of the molding compositions.For example, if shaped articles are to be manufactured which will not besubjected to extremely high temperatures, polyacrylonitriles can beused. For shaped articles subjected to relatively high thermal stressand strain differently based fibers, for example polyaramides and, inparticular, carbon fibers, are suitable. Provided the fiber-formingpolymers also form pulp, mixtures of pulps of triketoimidazolidineprecondensate and those polymers, such as polyacrylonitriles, can alsobe used. In this case, the solutions of the polymers used are mixed witheach other and conjointly sprayed. The fibers used can of course also besubjected to a customary pretreatment such as roughening of the surfaceor fibrilating by means of chemical and/or mechanical methods known, forexample, from paper production technology.

In a further embodiment, the molding compositions can be improved stillfurther by leaving a small amount, for example up to 15% by weight, ofaprotic, strongly polar solvents, for example of the abovementionedsolvents, in the pulps or composites. This small amount can be, forexample, 1-10, preferably 2 to 5% by weight. Adoption of this measurecan achieve that the products remain fluid under pressure and at anelevated temperature and behave like thermoplastics which have excellentadhesion to the other components of the molding compositions. In othercases it has been found to be advantageous to reduce the solvent contentto less than 1, preferably to less than 0.5, % by weight.

The portions of pulp are obtained in amorphous form even in thecomposites and thus produce the abovementioned advantages.

The triketoimidazolidine precondensates mentioned are as a rule preparedby reacting bis-oxamide esters with diisocyanates alone or combined withat least dibasic carboxylic acids at an elevated temperature, forexample from 50 to 200, preferably 50° to 180° C. Examples of suchreactions are described in German Pat. No. 1,916,932, GermanOffenlegungsschrift No. 1,920,845, German Offenlegungsschrift No.2,030,233, German Offenlegungsschrift No. 2,139,005 and GermanOffenlegungsschrift No. 2,303,239. The expression "precondensates"indicates not only the polymeric or oligomeric character of thesesubstances but also their capacity for further reaction involvingenlargement of the molecule. The precondensate can be prepared in acustomary manner from bis-oxamide esters and diisocyanates alone orcombined with at least dibasic polycarboxylic acids at an elevatedtemperature, for example within a range of 50 to 200, preferably 50° to180, °C. Suitable components are in particular4,4'-bis(ethoxalylamino)diphenylmethane, trimellitic anhydride and4,4'-diisocyanatodiphenylmethane. The precondensate can be converted,and solidified at 150 to 480, preferably 180° to 350, °C. to give aproduct with a higher molecular weight.

The reactive terminal groups of the precondensates, i.e. the oxamideester groups and the isocyanate and/or urethane groups, can react underthe conditions under which molding compositions are processed also withthe remaining reactive components or with one another to give new2,4,5-triketoimidazolidine rings and an increased molecular weightand/or with the remaining reactive components of mixtures according tothe invention. This leads to a still more intensive degree of bondingbetween the triketoimidazolidines and the other reactive substances, sothat very stable adhesion is obtained in addition to the strengtheningeffect. In certain cases, a small content of solvents, for example ofN-methylpyrrolidone, in the triketoimidazolidine can benefit this effectfurther. The ability to increase the weight of the molecule is aconsiderable advantage over polyaramide systems, because low molecularweight systems having low viscosity, ready solubility and otherproperties essential for easy processability may be used which can beconverted, for example by treatment at an elevated temperature, intohigh molecular weight systems with simultaneous shaping are suitable formolding compositions in accordance with the invention.

In the pulps the triketo compounds are present in the form of fibrids,ie. finely divided fibers, whose length and diameter can vary withinwide limits, similar to the case of asbestos where this is alsoconsidered a desirable property. In general the length is more than 1 mmand the diameter is more than 2, preferably at least 3, μm. If desired,length and diameter can also be chosen to be smaller. The use of thecomposites represents no risk whatsoever, either of respirability or tothe processor.

The properties of the fibrids can be largely controlled by suitablechoice of the conditions in the preparation of the pulp, such asconcentration in the solution, temperature, extrusion pressure andnozzle dimensions. Thus, for example, a higher concentration of triketocompounds causes the fibrids to be longer and have a greater diameter.By using low solvent concentrations and viscosities with correspondingoverpressure in the solution to be extruded it can be achieved that nocontinuous filament forms but a fibrid product is obtained. The choiceof nozzle diameter is critical especially for the diameter of thefibrids. If a non-solvent, for example alcohol, is added to the solutionto be extruded, relatively short and/or relatively thin fibrids can beobtained.

The surface properties of the fibrids depend not only on the extrusionpressure of the solution but also on the coagulation medium into whichthe solution is extruded. If the solution is extruded, for example, intothe non-solvent water, a large specific surface area is obtained. If, onthe other hand, the coagulation bath contains a portion of solvent forthe substance, for example of the abovementioned aprotic solvent, afibrid is obtained which is smooth and has a small specific surfacearea. The water retention capacity of fibers made of triketo compoundsis in general 8 to 200% by weight, usually about 10% by weight, whilethe water retention capacity of the pulp is usually between 50 and 200%by weight. The larger the specific surface area the larger the waterretention capacity. The specific surface area of the pulp or oftriketoimidazolidine fibrids contained in the composites is, forexample, 10 to 100 m² /g, the fibrid length is in general in the mmrange, for example at most 10 mm, preferably at most 5 to 7 mm, and thefibrid diameter is within the μm range, for example at most 100 μm,preferably at most 30 μm.

The specific heat of the precondensates can vary according to thechemical structure of the triketo compounds. The specific heat can be,for example, 0.22 to 0.38, preferably 0.28 to 0.36 cal/(g.°C.). Thisparameter is of importance when shaped articles manufactured frommolding compositions according to the invention are subjected to, forexample, considerable mechanical stress, such as friction. The specificheat of this triketo compound is approximately equal to that ofasbestos. As in the case of the latter, excess heating by friction isalso avoided in shaped articles made from molding compositions accordingto the invention; the shaped articles manufactured therefrom have a goodheat resistance and dimensional stability under heat. The triketocompounds also have an excellent chemical resistance, in particular verygood resistance to alkali.

The fact, found by X-ray analysis, that triketo precondensates, inparticular the pulp component, do not contain any microcrystallinefractions whatsoever is of very high significance. Rather, they arecompletely amorphous. The fibers which can be used for compositeformation are admittedly crystalline, but do not contain anymicrocrystalline fractions of respirable dimensions. The result is thatthe fibers and the composite can also not be split into respirable smallparticles, as is the case with asbestos. As is known, the ratio of thelength to the diameter of asbestos particles is critical for the lungtoxicity. This ratio becomes established in the case of asbestos, interalia, by the ready divisibility and the typical crystal structure. Evenwhen grinding the amorphous materials used according to the invention,for example the composites, dusts having this ratio, characteristic forlung toxicity, of length to particle diameter can virtually not occur.

The fibrids and composites made of triketo compounds contained inmolding compositions according to the invention have the essentialadvantage that they, unlike asbestos, are dust-free; this factrepresents a considerable technical advance in that a source ofenvironmental pollution and a health hazard to the processing personnelas well as to consumers is abolished. A further advantageous property ofthe fibrids and composites is that the triketo compounds are resistantto oils, gasoline and grease, i.e. that their ability to absorb oil isparticularly low. This is of importance in particular in practice whenshaped articles manufactured from the molding compositions are used, forexample, in the motor vehicle sector, mechanical engineering, thebuilding sector or the like. Further advantages of the triketo compoundsused are that these compounds are not flammable and that no toxicproducts are formed under prolonged exposure to high temperatures, forexample to a source of ignition. The absence of dust in these products,already mentioned, represents a considerable advantage over theproperties of known shaped articles, for which asbestos has hithertobeen commonly used. On the other hand, properties such as tensilestrength and initial modulus are increased by the fiber componentcontained in the composite.

The ratio of component (a) to the remaining constituents, in particularto component (c), is in general so chosen that at least 15, preferablyat least 30, % of functional groups of component (c) react with thetriketo compounds.

Inorganic fillers of mineral, silicate and/or metallic nature and havinga high thermal resistance and--provided they are non-metallic fillers--alow heat conductivity, are advantageously used as fillers (b). Examplesof suitable fillers of this type are mineral powders such as crushedrock, crushed slate, marble powder, quartz sand, quartz powder, chalk,glass powder, glass fibers, graphite, metal powder, metal chips, metaloxides and customary inorganic pigments. It is also possible to useasbestos fibers as fillers, but only in a minor amount combined withother fillers if health-damaging consequences can be avoided.

Organic fillers such as cellulose fibers, for example wood flour orsawdust, cellulose derivatives, such as cellulose ethers or esters,organic pigments, such as phthalocyanines, quinacridones, anthraquinonepigments or the like, are also suitable. Elastomers and hydrocarbonresins, in each case without functional groups, can also be used asorganic fillers. Examples of such hydrocarbon resins are those ofmonoolefins and/or diolefins inclusive of cyclic monomers, such ascyclopentadiene or dicyclopentadiene, also of aromatics or of vinyl orallyl compounds or of hydrocarbon fractions as obtained in thedistillation of petroleum. Suitable elastomers are in particular naturalor synthetic rubbers, such as styrene rubber, acrylonitrile rubber,polybutadiene, butyl rubber, polyisoprene or ethylene/propylene/dieneterpolymer rubber in each case singly or mixed.

In particular cases it can also be advantageous also to add to themolding compositions as component (b), up to 80, preferably up to 20, %by weight, relative to the precondensate content of the pulp component,fibers having a high tensile strength and a high initial modulus, forspecific purposes, also having a high heat resistance (for example forthe purpose of further improving the properties of frictional articles),for example those mentioned above.

Suitable phenolic resins (component c) are resols or novolaks, thelatter together with suitable hardeners, such as hexamethylenetetramine,oxalic acid or the like. Phenol components which can be used are notonly unsubstituted but also substituted, monohydric or polyhydric,mononuclear or polynuclear phenols, such as phenol, resorcinol,pyrocatechol, bis-phenols, such as 4,4'-diphenylolpropane,4,4'-diphenylolmethane or their substitution products, such as monoalkylor polyalkyl derivatives, for example butylphenol or octylphenol, assuch or in the form of mixtures. In particular formaldehyde is possiblefor use as the aldehyde component.

Suitable amine resins are urea resins, guanamine resins, but preferablymelamine resins or their substitution or etherification products, inparticular their alkyl derivatives. Also in this case is in particularformaldehyde possible for use as the aldehyde component.

The epoxide resins can be of the aromatic, aliphatic and/orcycloaliphatic type. Examples of suitable epoxide resins are resinscontaining glycidyl ester and/or ether groups, epoxidized oils,epoxidized fatty acids and their esters, epoxidized polyhydroxycompounds, sugar derivatives having glycidyl radicals, but preferablypolyepoxides based on 4,4'-diphenylolpropane and/or4,4'-diphenylolmethane and epihalogenohydrin, preferablyepichlorohydrin.

Suitable polyester resins are customary unsaturated and/or saturatedpolyesters, alkyd resins, polyether-esters, polyesters which containamide and/or imide groups but which in each case still have free OHand/or COOH groups, or copolymers having ester groups and also OH and/orCOOH groups.

Examples of suitable reactive hydrocarbon resins are those which are inaddition modified with a carboxylic acid, its anhydride or otherreactive groups, such as hydroxyl-containing ester groups or sulfhydryl,sulfide, disulfide and/or sulfochloride groups. Thus, for example,prevulcanized butadiene, isoprene or chloroprene polymers or evensulfochlorinated polyethylene are possible for use as reactiveelastomers. Examples of other suitable reactive polymers are acrylicresins having free OH, NH₂, ##STR1## CONH₂ and/or COOH groups in which Ris alkyl having, for example, 1 to 8 C atoms.

Molding compositions according to the invention have the advantage thatenvironmentally they are considerably more acceptable than comparablecompositions containing a significant amount of asbestos fibers.

The triketo compounds and, in particular, the composites are used inmany and varied fashion for manufacturing shaped articles. The pulp ofthe triketo compounds is distinguished by particularly firm adhesion toa very wide variety of materials, such as to the other fillers and thereactive binder. The triketo compounds and, in particular, thecomposites are highly suitable for strengthening and reinforcing themolding compositions according to the invention. The moldingcompositions can advantageously be used, inter alia owing to the goodalkali resistance of the precondensate, for reinforcingcement-containing shaped parts, for example boards. They are also veryhighly suitable for those shaped articles which are exposed to strongradiation, light, heat and/or mechanical action, such as shaped parts,for medical, industrial and domestic purposes, for example in bonesurgery, as elements in mechanical engineering and aircraft, ship andautomotive construction, as structural members in electricalengineering, for example for handles and insulating material, inelectronics, for example for conductor boards as well as for fittings,clutch, brake and frictional linings, or frictional elements, that is,for example, clutch disks, in particular in the frictional wheel field,and for cylinder head seals or in the building field as structuralmembers for example building boards, thermal insulating material, floorcoverings, roof coverings or the like, and also for manufacturingheat-stable as well as chemical-resistant sealing materials.

The invention finally also relates to a process for preparing acomposite from triketoimidazolidine precondensate pulp and fibers,wherein the solution of a triketoimidazolidine precondensate in organicsolvents which are preferably aprotic, like the examples mentionedabove, and miscible with the solvents mentioned below is sprayedsimultaneously with, but separately from, the fibers or injected into asuspension of fibers in a coagulation bath, for example halogenated,particularly chlorinated, hydrocarbons, such as methylene chloride,chloroform or carbon tetrachloride, or water, in which the precondensateand the fiber are not soluble. Composites of this type are distinguishedby the fact that the fibers used are bonded essentially in tangledposition to the pulp.

In the experiments described below % denotes % by weight.

I. PREPARATION OF THE TRIKETOIMIDAZOLIDINES

(A) 199 g of 4,4'-bis-(ethoxalylamine)-diphenylmethane (0.5 mole) and 96g of trimellitic anhydride (0.5 mole) were heated after 1 g of lithiumbenzoate and 5 ml of tributylamine (water content less than 0.05%) hadbeen added to 120° C. together with 544 g of N-methylpyrrolidone, andthe mixture was added in the course of 30 minutes to 250 g of4,4'-diisocyanatodiphenylmethane. The batch was then stirred for 4 to 6hours at 120° C. until the elimination of CO₂ was complete. After thebatch had cooled down, 1,060 g of a clear, red-brown, highly viscouscondensate solution were obtained. Solids content: about 50%.

(B) 400 g (1 mole) of 4,4-diethoxalylaminodiphenyl ether were stirred atroom temperature with 252 g (1 mole) of 4,4'-diisocyanatodiphenyl etherand 650 g of N-methylpyrrolidone. 7 ml of tri-n-butylamine were added tothe pasty mixture. The temperature increased to about 60° C. The mixturewas then stirred for 6 hours without heat being supplied. The clear,brownish-yellow solution thus obtained had a viscosity of about 1,400 cP(20° C.)

(C) 398 g (1 mole) of 4,4'-diethoxalylaminodiphenylmethane weredissolved at 70° C. in 800 g of N-methylpyrrolidone with the addition of0 ml of triethylamine; 500 g (2 moles) of4,4'-diisocyanatodiphenylmethane were added in portions. The temperaturedid not exceed 80° to 85° C. After the addition was complete, the batchwas stirred for a further 6 hours at room temperature and then dilutedwith 100 g of a mixture of phenol and cresol (ratio of 1:1). A clear,yellow solution was obtained.

(D) 756 g (3 moles) of 4,4'-diisocyanatodiphenyl ether were heated to100° C. in 1,154 g of a N-methylpyrrolidone/cyclohexanone mixture (ratioby weight 30:70), and the hot mixture was added after 20 ml oftriethylamine had been added in the course of 2 hours to 398 g (1 mole)of bis-(ethoxalylamino)-diphenylmethane. 161 g (0.5 mole) ofbenzophenonetetracarboxylic acid dianhydride were added after 45 minutesin the course of one hour with vigorous stirring. During this additionthe viscosity increased very considerably. After stirring for threehours at 100° to 110° C. a clear, red-brown polymer solution wasobtained. Yield: 2,400 g (solids content: about 52%).

(E) 272 g (0.5 mole) of 4,4'-bis-(4-carboxyphthalimido)-diphenylmethaneand 199 g (0.5 mole) of 4,4'-bisethoxalylamino)-diphenylmethane wereheated to 120° C. in 1,040 g of N-methylpyrrolidone, 5 ml oftributylamine were added, and the mixture was added in the course of 90minutes to 375 g (1.5 moles) of 4,4'-diisocyanatodiphenylmethane. Finecrystals precipitated from the originally clear solution.

The condensation reaction was then carried out at 190° to 198° C. untilthe now completely clear, viscous reaction mixture produced a clear,viscous polymer solution at room temperature. This was the case afterabout eight to ten hours. Yield: 1,790 g of a clear, highly viscouspolymer solution.

(F) 98.4 g (0.2 mole) of crude 1,4-bis-(p-ethoxalylaminophenoxy)-benzene(melting point 165° C.) and 19.2 g (0.1 mole) of trimellitic anhydridewere dissolved at 130° C. in 100 ml of dimethylacetamide, and 0.5 ml oftribenzylamine was added to the solution. A mixture of 47.5 g (0.15mole) of 4,4'-diisocyanatodiphenylmethane and 45.4 g (0.18 mole) of4,4'-diisocyanatodiphenyl ether was added at this temperature in thecourse of one hour. The batch was then stirred at 140° C. for fourhours, cooled down to 70° C. and stirred into 100 g of a technical-gradecresol mixture. After the batch had cooled down to room temperature 402g of a clear, highly viscous polymer solution the solids contents ofwhich was about 50% were obtained.

(G) 564 g (1 mole) of 4,4'-bis-(4-carboxyphthalimido)-diphenyl sulfone,and 548 g (1 mole) of 4,4'-bis(4-carboxyphthalimido)-diphenyl ether weresuspended at 60° C. in 2,800 ml of N-methylpyrrolidone and 2,000 ml ofdimethyl sulfoxide in a 10 liter three-necked flask. 67 g (0.2 mole) ofthe azomethine (melting point=300° C. with decomposition) formed from2-hydroxynaphth-1-aldehyde and 5-aminoisophthalic acid were then added.The mixture was then heated to 140° C. 199 g (0.5 mole) of4,4'-bis-(ethoxalylamino)-diphenylmethane, 176.4 g (0.7 mole) of4,4'-diisocyanatodiphenyl ether and 500 g (2.0 moles) of4,4'-diisocyanatodiphenylmethane were added at this temperature in thecourse of 3 hours. The batch was stirred at 150° C. until theelimination of CO₂ was complete (about 6 to 8 hours). The temperaturewas increased to 200° C., after 2 g of tributylamine had been added, andmaintained for 4 hours. 400 ml of cyclohexanone and 200 ml ofdiethylbenzene were then added to dilute the batch. After cooling down apale orange-yellow, highly viscous polymer solution was obtained. Thesolids content was about 25% by weight. Yield: 7,200 g. The inherentviscosity of the polymer was 0.44 (20° C.), measured in a 1% strengthsolution.

(H) 158.5 g (0.8 mole) of 4,4'-diaminodiphenylmethane were dissolved atroom temperature with stirring in 1,280 ml of N-methylpyrrolidone. 307.2g (1.6 moles) of trimellitic anhydride were then added in portions at80° C. After toluene had been added as an azeotropic agent, thetemperature was increased to 180° C. and the condensation reaction wascontinued until no more water was eliminated. This was the case afterabout 2 hours. 79.6 g (0.2 mole) of4,4'-bis-(ethoxalylamino)-diphenylmethane and 11.4 g (0.04 mole) ofazomethine (melting point=287° C.) formed from 5-aminoisophthalic acidand salicylaldehyde were then added. After the mixture had been cooleddown to 160° C., 250 g (1 mole) of 4,4'-diisocyanatodiphenylmethane wereadded. The condensation reaction was carried out at 160° to 180° C.until the elimination of CO₂ was complete. The temperature was thenincreased to 205° C., and the alcohol liberated in the condensation wasdistilled off via a packed column in such a way that the headtemperature did not exceed 125° C. The batch was then cooled down anddiluted with 100 ml of dimethylacetamide, 100 ml ofhexamethylphosphoramide and 90 ml of cyclohexanone.

2,300 g of a yellow-brown, highly viscous solution containing about 31%of solids were obtained. The inherent viscosity of the polymer, measuredin a 1% strength solution, was 0.50 (20° C.)

(I) 218.4 g (0.4 mole) of 4,4'-bis(4-carboxyphthalimido)-diphenylmethaneand 3.55 g (0.01 mole) of 5-(4-carboxyphthalimido)-isophthalic acid weredissolved in 400 ml of N-methylpyrrolidone, and the solution was stirredat 120° C. into 39.8 g (0.1 mole) of4,4'-bis(ethoxalylamino)-diphenylmethane. After the batch had cooleddown to 100° C. a solution of 130 g (0.52 mole) of4,4'-diisocyanatodiphenylmethane in 260 ml of N-methylpyrrolidone wasadded dropwise in the course of 2 hours. 0.5 g of dibutyltin dilauratewas then added and the condensation was carried out at 170° C. until theelimination of CO₂ was complete. The temperature was increased to 200°C. and 2.85 g (0.01 mole) of the azomethine formed from5-aminoisophthalic acid and salicylaldehyde was added. The alcoholliberated in the condensation was distilled off at this temperature asdescribed in Example H. The batch was then heated to 205° C., 4.9 g ofcobalt octoate, dissolved in 20 g of dimethyl sulfoxide, were added, andthe batch was diluted with 200 ml of N-methylpyrrolidone. After thebatch had cooled down to room temperature 1,150 g of a clear, highlyviscous, brown-orange solution having a solids content of about 29% wereobtained. Inherent viscosity: 0.67 (1% strength solution of the solidpolymer in N-methylpyrrolidone at 20° C.).

(J) 79.2 g (0.4 mole) of 4,4'-diaminodiphenylmethane and 153.6 g (0.8mole) of trimellitic anhydride were stirred with 200 ml ofN-methylpyrrolidone and 200 ml of dimethyl sulfoxide. After xylene hadbeen added as an azeotropic agent the condensation was carried out at190° C. until H₂ O was no longer eliminated. The batch was then cooleddown to 120° C. and 2.5 g of triethylamine and 0.5 g of butyl titanatewere added. 39.8 g (0.1 mole) of the azomethine formed from5-aminoisophthalic acid and 2-hydroxynaphth-1-aldehyde were then added.130 g (0.52 mole) of 4,4'-diisocyanatodiphenylmethane dissolved in 260ml of N-methylpyrrolidone were then added dropwise at 100° C. in thecourse of one hour. After the addition was complete the batch was heatedto 202° C. and the condensation was completed at this temperature in thecourse of 6 hours. After the batch had cooled down to 160° C. it wasdiluted with 200 ml of cyclohexanone. 1,160 g of a pale yellow and clearpolymer solution containing about 30% of solids were obtained. Theviscosity of the solution was about 24,000 cP (20° C.).

II. PREPARATION OF THE FILLERS AND COMPOSITES

(A) A 12% strength triketoimidazolidine precondensate solution inaccordance with I(A) was heated with stirring in a pressure vessel. Thehot solution was let down, through a spray tube, into a receptaclefilled with water. The resulting wet pulp was filtered from the waterand freed by washing from N-methylpyrrolidone. The washed pulp waswhirled about in a fluid mixer and then dried in a vacuum dryingcabinet. The pulp obtained had a bulk density of 33.3 g/l, a residualcontent of N-methylpyrrolidone of 0.2%, and a water retention capacity(in accordance with DIN 53,814) of 161.3%. The specific surface area was39 m² /g: length of the fibrids 1 to 3 mm, diameter about 3 to 8 μm.

(B) A 12% strength solution of the triketoimidazolidine in accordancewith I(B) in N-methylpyrroliddone was fed in portions into an autoclave.This solution was sprayed from the autoclave at room temperature underan over-pressure by means of compressed air into running water. The wetpulp was washed with water and then dried in a circulating air cabinetto a residual moisture content of 2.5%. The longest fibrids in the pulphave a length of 7 mm and a diameter of about 12 μm.

(C) A 30% strength deaerated and warmed solution at 40° C. of theprecondensate prepared in accordance with I(H), in N-methylpyrrolidone,was spun into filaments through a spinneret and via a dry-spinningchamber. The filament was taken out of the chamber and wound up. Thefilament, subsequently washed with hot water, was stretched at anelevated temperature and then cut into 100 mm long staple fiber. Thefiber had a titer of 1.9 dtex, a tensile strength of 26 cN/tex and anelongation at break of 6%. The fiber still contained 1.6% ofN-methylpyrrolidone.

(D) A 22% strength solution of the precondensate prepared in accordancewith I.(I), in N-methylpyrrolidone, was spun into filaments on awet-spinning line. The hot solution at 60° C. was spun through aspinneret into an aqueous coagulating bath containing hotN-methylpyrrolidone. The filament was wet-stretched via takeup rolls ina heated stretching bath. The filament was then dried on hot rolls,stretched again and wound up. The filament obtained had an individualtiter of 15.5 dtex., a tensile strength of 10 cN/tex and an elongationat break of 40%, and shrunk by 0.1% on boiling. The filament was cutinto a 2.6 mm long staple fiber.

Some of the cut fibers were dispersed in water, fibrilated by frictionon a set of rolls (refiner) and dried in a thin layer at roomtemperature.

(E) A 12% strength solution of the precondensate in accordance withI(A), N-methylpyrrolidone, was let down from an autoclave at roomtemperature under an overpressure by means of compressed air into avessel filled with water in which an amount, of the same weight as theprecondensate, of 4.4 mm long 1.9 dtex polyacrylonitrile fibers wassuspended. The wet composite of pulp and fibers obtained in the sprayingwas filtered from the water and freed from N-methylpyrrolidone bywashing. The washed composite was whirled about in a fluid mixer andthen dried in a drying cabinet under reduced pressure. The length offibrids in the pulp was 2 to 6 mm and the diameter was 5-12 μm.

(F) The procedure of II(B) was repeated with the difference that asolution of the precondensate in accordance with I(C) inN-methylpyrrolidone, was mixed with stirring with the same amount byweight of a 10% strength solution of polyacrylonitrile indimethylformamide and then processed. The longest fibrids in the pulpwere 10 mm long; the diameter was about 15 μm.

III. MOLDING COMPOSITIONS (Examples 1 to 12)

(1) A solution of 850 g of a phenol novolak (molar ratio phenol:formaldehyde=1:0.85), which had been prepared in the presence of 9 g ofhydrochloric acid as a catalyst, and of 150 g of hexamethylenetetraminein 1,000 g of methanol was stirred at 80° C. until a dispersion hadformed, i.e. incompatibility with the solvent had arisen. Thisapproximately 50% strength dispersion was processed into a moldingcomposition for the impregnation method as follows: 8 kg of the fibridsin accordance with II(A) were mixed in a kneader having sigma bladeswith 5.74 kg of this dispersion, 100 g of zinc stearate as lubricant, 20g of partially hydrolyzed ester wax and 140 g of nigrosine base as blackdyestuff. The solvent was then removed by drying at 80° C. A moldingcomposition was obtained in the form of freeflowing granules having avery uniform particle size.

(2) 8 kg of a 50% strength solution of an epoxide resin novolak preparedfrom bisphenol A and epichlorohydrin in a molar ratio of 1:2.2 (epoxidenumber 6.6 and molecular weight 600), in methyl ethyl ketone, wasstirred at 40° to 80° C. with 400 g of diethylenetriamine until adispersion had formed. 4 kg of this approximately 50% strengthdispersion were mixed as in Example 1 with 1.1 kg of glass fibers(staple length 6 mm), 1.1 kg of dried pulp in accordance with II(B),3.74 kg of limestone, 100 g of zinc stearate and 20 g of partiallyhydrolyzed ester wax and further processed as in Example 1. Afterremoval of the solvent the molding composition obtained ispreferentially suitable for shaped parts in electrical engineering. Adifferent aliphatic polyamine can also be used instead of thediethylenetriamine.

(3) 8 kg of a 50% strength acetone solution of an unsaturated polyesterresin to which 40 g of cyclohexanone peroxide had been added andcomposed of 2 moles of maleic anhydride, 1 mole of phthalic anhydrideand 3 moles of propane-1,3-diol was polymerized at 80° to 90° C. untilthe product was incompatible with acetone. The polymerization wasstopped by adding 0.5% by weight of hydroquinone, relative to polyester,as an inhibitor. The dispersion was processed into a molding compositionas in Example 2.

(4) The condensation of a melamine resin from melamine and aqueousformaldehyde (30% strength) in a molar ratio ofmelamine:formaldehyde=1:1.8 was catalyzed with an amount of bariumhydroxide solution such that a pH value of 8.8 was produced in thesolution. The state at which a dispersion started to form in the aqueousphase was arrested as soon as a solid phase appeared. 8 kg of thisapproximately 50% strength dispersion were mixed with 4.88 kg ofwollastonite, 1 kg of the fibers in accordance with II(C), 100 g ofcalcium stearate and 20 g of a commercially available fatty acid amideand further processed into a molding composition, both steps beingcarried out as in Example 1.

(5) A batch of 400 g of a crystallizable, melted, unsaturated polyesterof equivalent amounts of 2,2-dimethylpropane-1,3-diol and dicarboxylicacid comprised of 90 mole % of fumaric acid and 10 mole % ofterephthalic acid, 60 g of diallyl phthalate, 60 g of styrene, 30 g of a50% strength solution of benzoyl peroxide in dioctyl phthalate, 30 g ofzinc stearate and 820 g of limestone was processed in a heated mixer at40° to 50° C. After homogenization 450 g of a fiber in accordance withII(B) and having a length of about 6.5 mm were added to the mass. Thevoluminous warm material solidified after a brief time at roomtemperature. The texture was further improved for the moldingcomposition by treatment in a cross beater mill.

(6) 400 g of a crystallizable, melted, unsaturated polyester of 50 mole% of diphenylolpropanedioxyalkyl ether, 25 mole % of fumaric acid and 25mole % of terephthalic acid, 80 g of diallyl phthalate, 30 g of a 50%strength solution of benzoyl peroxide in dimethyl phthalate, 30 g ofzinc stearate, 1,200 g of limestone, 120 g of kaolin and 180 g of afiber in accordance with II(A) and having a length of about 2.5 mm weremixed in a heated mixer at 50° C., and the doughy warm mass was passedthrough unheated rolls. The thin skin obtained became rigid after ashort time at room temperature. After comminution in a cross beater milla dry, non-caking, free-flowing molding composition was obtained.

(7 to 12) Examples 1 to 6 were repeated with the difference that fibridsor pulp or fibers were in each case replaced by the same amount byweight of composites, namely:

Example 7: 8 kg of composite in accordance with II(E).

Examples 8 and 9: 1.1 kg each of the mixed pulp in accordance with II(F)

Example 10: 1 kg of composite in accordance with II(E)

Examples 11: 450 g of composite in accordance with II(E)

Example 12: 180 g of the composite in accordance with II F and inaddition 60 g of a polyaramide fiber having a length of 4.4 mm and alinear density of 2.4 dtex.

We claim:
 1. A molding composition comprising(a)2,4,5-triketoimidazolidine precondensates having terminal groupsselected from oxamide esters groups, urethane groups, isocyanate groupsand combinations thereof in the form of an amorphous precondensate as areactive filler, (b) a customary filler selected from the groupconsisting of organic fillers, inorganic fillers and combinationsthereof, and (c) at least one further reactive component of a binderwhich is a polymerization resin having functional groups.
 2. A moldingcomposition as claimed in claim 1, wherein component (a) is a reactionproduct of a bis(oxamide ester) and a diisocyanate or of a bis(oxamideester), a diisocyanate and a polycarboxylic acid.
 3. A moldingcomposition as claimed in claim 1, wherein component (a) is presenttogether with a filler (b) selected from the group consisting ofcellulose, cellulose derivatives, elastomers and combinations thereof.4. A molding composition as claimed in claim 1, wherein component (a) ispresent in the form of a pulp having at least one of the followingcharacteristics: specific surface in the range from 10 to 100 m² /g;length of the fibrids at most 10 mm; diameter of the fibrids at most 100μm; specific heat 0.22 to 0.38 cal/g°C.; water retention capacity 50 to200% by weight.
 5. A molding composition as claimed in claim 1, whereincomponent (a) is used in the form of a product which does not containmore than 1% by weight of an aprotic, strongly polar solvent.
 6. Amolding composition as claimed in claim 1, wherein the filler (b) is amineral or silicate or metal or a combination thereof, each having ahigh thermal load resistance and wherein the mineral and silicate fillerhas a low heat conductivity.
 7. A molding composition as claimed inclaim 1 comprising:(a) 2,4,5-triketoimidazolidine precondensates havingterminal groups selected from oxamide ester groups, urethane groups,isocyanate groups and combinations thereof in the form of an amorphousprecondensate of a bis(oxamide ester) and a diisocyanate or of abis(oxamide ester), a diisocyanate and a polycarboxylic acid, as areactive filler, (b) a customary filler selected from the groupconsisting of organic fillers, inorganic fillers and combinationsthereof and (c) at least one further reactive component of a binderwhich is a polymerization resin having functional groups, component (a)being present in the form of a pulp having at least one of the followingcharacteristics: specific surface in the range from 10 to 100 m² /g;length of the fibrids at most 7 mm; diameter of the fibrids at most 30μm; specific heat 0.28 to 0.36 cal/g°C.; water retention capacity 50 to200% by weight.
 8. A shaped article comprising the hardened shapedmolding composition as claimed in claim
 1. 9. An article as claimed inclaim 8 which is in the form of a brake lining or a clutch disk.
 10. Anarticle as claimed in claim 8, which is in the form of a cylinder headseal.
 11. A molding composition comprising(a) 2,4,5-triketoimidazolidineprecondensates having terminal groups selected from the oxamide estergroups, urethane groups, isocyanate groups and combinations thereof inthe form of an amorphous precondensate as a reactive filler, (b) atleast one further reactive component of a binder which is apolymerization resin having functional groups.
 12. A molding compositioncomprising(a) 2,4,5-triketoimidazolidine precondensates having terminalgroups selected from oxamide ester groups, urethane groups, isocyanategroups and combinations thereof in the form of an amorphousprecondensate as a reactive filler, (b) a customary filler selected fromthe group consisting of organic fillers, inorganic fillers andcombinations thereof, and (c) at least one hydrocarbon resin havingfunctional groups.
 13. A molding composition as claimed in claim 1wherein the polymerisation resin is a polycondensation resin selectedfrom the group consisting of phenolic resins, amino resins and epoxyresins.
 14. A molding composition as claimed in claim 1, wherein thepolymerisation resin is a polyester resin.
 15. A molding composition asclaimed in claim 7, wherein the polymerisation resin is selected fromthe group consisting of phenolic resins, amino resins, epoxy resins,polyester resins and hydrocarbon resins.
 16. A molding composition asclaimed in claim 11, wherein the polymerisation resin is selected fromthe group consisting of phenolic resins, amino resins, epoxy resins,polyester resins and hydrocarbon resins.